here's abc's rob nelson. >> reporter: no dreaming necessary this year. it is going to be a white christmas for large portions of the u.s., from new england to california's sierra mountains. >> this is as white as we want it to be. >> reporter: but for many, it's turned their simple over the river and through the woods holiday trip, into a chaotic travel nightmare. >> we are hoping we don't sit on the runway. >> reporter: it's no picnic for the little travelers, either. >> want to get there. we're going to be late. come on. >> reporter: a storm is forecast to hit oklahoma this morning. the midwest will see themselves socked with snow by wednesday, which may end up inconveniencing tens of millions of travelers on the day after christmas, one of the heaviest travel days of the whole year. >> most people traveling for the holidays in six years. >> reporter: northern california's snowfall, more than six feet in the sierra mountains, caused the grounding of hundreds of flights in the san francisco area. >> found out my flight had been canceled after four hours